Apparatus for producing an endless sheet of electrolytic copper



Feb. 13, 1968 A. PEDONE 3,368,959

APPARATUS FOR PRODUCING AN ENDLESS SHEET OF ELECTROLYTIC COPPER FiledNov. 18, 1963 INVENTOR. ,4 V600 yr BYJb/q/w United States Patent Ofi ice3,368,959 Patented Feb. 13, 1968 3,368,959 APPARATUS FOR PRODUCING ANENDLESS SHEET F ELECTROLYTIC COPPER Antonio Pedone, Vivaio St., Milan,Italy Filed Nov. 18, 1963, Ser. No. 324,574 2 Claims. (Cl. 204--202)ABSTRACT OF THE DISCLOSURE This invention relates to an apparatus forcontinuously producing a strip of electrolytic copper, including anelectrolyte tank, a travelling endless belt conveyor-like cathode havingan upper and a lower substantially horizontal strands and an externalsurface of the lower strand immersed in the electrolyte for continuouslydepositing thereon copper by electrolysis as said surface is moved inimmersed condition along said tank and an inner sur face opposite tosaid external surface, means to move said belt conveyor-like cathode,anodes disposed in said tank in proximity of said immersed externalsurface, means for continuously stripping the deposited copper in theform of band from said belt conveyor-like cathode.

The present invention relates to an apparatus for producing an endlesssheet of electrolytic copper.

Up to the present, very long and thin copper sheets have been producedby rolling cast copper plates. This process has several drawbacks, amongthem the following:

The copper is somewhat contaminated duringthe casting process, andtherefore 99.99% purity cannot be obtained, as achieved with theelectrolytic system.

In the rolling process, the in-products are bars of considerablethickness, which are reduced to thick plates, from which the thin sheetis obtained after repeated passes of the same between the cylinders ofthe rolling mill.

The thin sheet thus obtained is composed of copper fatigated by the veryhigh pressures exerted to reduce the thickness in such a great extent;therefore, the material requires further treatment before being readyfor utilization in its different applications.

The main object of this invention is to obtain an apparatus which canproduce electrolytically a practically endless copper sheet, of thedesired thickness, having the referred maximum percentage of purity,that can be utilized without requiring any further treatment.

Another fundamental object of this invention is to provide the referredapparatus With large anodic and cathodic working surfaces, in order toachieve a greater production, in terms of pounds of electrolytic coppersheet, without requiring higher consumption of electrical energy perpound.

In order that the present invention may be more clearly understood, oneof its preferred embodiments is shown schematically, as a non-limitativeexample, in the accompanying drawing in which:

FIGURE II, a lateral view in elevation and longitudinal section, showingthe general arrangement of the different component parts of theapparatus.

FIGURE 2, a cross section view.

FIGURE 3, a partial view of FIGURE 2, in enlarged scale.

FIGURE 4, a cross section view of one of the copper anodes, and

FIGURE 5, a partial view of FIGURE 2, showing an alternative arrangementof the electrolyte stirrer.

Same reference characters indicate similar elements or component partsthroughout the figures.

The apparatus consists of a movable cathode A formed by an endlessconducting belt conveyor-like band a, made,

for example, of stainless steel, extending over and between twocylindrical drums b-c that have horizontal shafts 1 placed in the samehorizontal plane, whereby the upper and lower rectilinear sections 2 and3 of the belt conveyor-like band are arranged horizontally. The drumsare mounted on shafts 1, which in turn are rotatably mounted with theirends on corresponding supports, and one of them or both are connected-toconventional driving means, for example, an electric motor, through aspeed reducing mechanism.

Both drums bc are somewhat narrower than the width of band a, in orderto leave their both edge portions free; said edge portions beingprovided each with a side wall member d that is elastically flexible andprojects perpendicularly from the inner surface of the band. This sidewall member is made of a non-conducting material, such as rubber or aplastic.

The lower rectilinear section or strand 2 of the band is arranged insidea cell e containing the electrolyte f; the maximum level of theelectrolytic charge does not reach the tops of side wall members d insaid lower section, and therefore the side wall members act ascontaining walls preventing the electrolyte to cover the inner surfaceof band a, Which remains uncovered, not contacting the electrolyte.

The purpose of this particular arrangement is to utilize the entireinner surface of said lower section 2 of band a for making contact withthe negative pole of the direct current electric power supply, andtherefore prevent concentration of the density of current at a point ofsaid strand.

A plurality of brushes g make sliding contact with this band innersurface, and are connected to the negative pole, each brush beingformed, for example, by a roll 4 of flexible copper strip wound around aflexible steel tube 6; said rolls are aligned in rows arranged at rightangle With the band, and the rolls of each row are conductively fixedwith their first turn to a common conducting bar 5 which supports andsupplies them With electric current.

Each copper roll 4 is slack in order to render it flexible, thusensuring maximum and continuous contact between the roll and the band;said contact is maintained by the weight of the flexible steel tube 6around which are wound the rolls of each row, and presses their lowerportion against band a.

The quantity of such rows depends on the length of said lowerrectilinear section 2 of band a.

The electric current passes to bars 5 and through brushes g isdistributed over the inner surface of section 2 of band a.

The copper that will deposit electrolytically over the band can come outfrom the electrolyte f itself or be emlitted by copper anodes h placedat the bottom of cel e.

In the first case, the cell bottom 7 is lined with a lead lining 8acting as an insoluble anode, and the electrolyte is a solution ofcopper salts, its concentration being maintained substantially constantby means of a recirculation system that dosifies it from outside thecell.

In the second case, the cell bottom is lined with a lining 8 thatdistributes the positive current to a plurality of copper anodes h whichemit the copper that deposits on band a.

Said anodes are constituted by copper plates seating through their flatlower surfaces on the lead lining 8 at the cell bottom 7, their uppersurfaces being parallel and facing the outer surface (in contact withelectrolyte) of the lower section 2 of band a. The upper surface of eachanode has a plurality of parallel and uniformily spaced grooves arrangedtransversally to the band, which define projections 10 having acute tops10' (FIG. 5),

through which the electric current comes out towards the band, accordingto the well known pin effect.

Consequently, copper is emitted from said tops uniformily across theupper face of each anode, in a somewhat fan like fashion and migratestowards the band, across the mass of electrolyte.

In order to avoid excessive tauting of the band to prevent sagging ofits lower section 2 due to its own weight, a non-conducting supportingrail 12 (FIG. 3), made of plastic material for example, is provided ateach lateral wall 11 of cell 2, adjacent to each longitudinal edge ofsaid lower section. The rail is formed by a large and rigid wing thatprojects from the inner side of said wall, its top face providing asliding race for the adjacent marginal portion of band a.

The hand does not rest directly upon said race, but through a portion ofthe body of the side wall member d applied at the band edge, which actslike a skate 13 projecting from its lower surface.

The rail 12 extends somewhat further from said skate, underneath saidmarginal portion of the band and is uniformly spaced from same, wherebyit actuates as a screen interposed between this portion and the copperanodes h, precluding a strai ht path of cations emitted by the anodesand migrating towards said portion, and forces them to pass next to theintermediate zone of the band, before reaching the marginal zones,whereby some of said cations adhere to said intermediate zone, and therest to the marginal zones.

Thus, concentration of cations, by pin effect, over the band edges,acting in this case as pins, is prevented; therefore, over-thickness ofthe marginal zone of the copper coat formed over the band is prevented.

A stirrer i for the electrolyte is provided underneath the lower section2 of the band, in order to disperse the anions and cations travellingacross the electrolyte.

The stirrer is formed by a plurality of parallel blades 14 arrangedtransverse to the band, and fixed through their ends to two posts 15,one arranged at each lateral wall of cell c.

The stirrer is located parallelly in a horizontally plane, underneaththe lower section of the band, and is longitudinally slidably mounted,for oscillating movement, in corresponding guides of the cell, eachguide being formed by one of said rails 12 that support the lowersection of the band, and by another rail 16 (FIG. 3) located underneaththe latter; said posts of the stirrer slide in between these two rails.

One end of said stirrer i is connected to means (not illustrated) thatdrive it with an oscillating motion.

The stirrer is made of a non-conducting material, such as plastics orwood.

A device j is arranged above the upper rectilinear section 1 of band a,for removing the anhydrous copper sulphate that remains on its externalsurface.

This device 1' is composed by at least one brush 17 having hardbristles, made for instance of steel, and is applied under certainpressure on said external surface of the copper, over which itoscillates in a transverse direction, mounted in related guides andconnected to driving means (not illustrated).

A brush having soft bristles 18 is located behind said brush with hardbristles 17, in order to clean from the external surface of the coppercoat, the material removed by the first brush 17, and displace ittowards the band edges.

This brush oscillates in a transverse direction relative the band a,mounted in corresponding guides, and connected to driving means (notillustrated).

The referred copper coat is detached from hand a at the portion wherethe latter starts curving over the second drum 0 on its way towards thecell c, and is guided by a free rotating cylinder 19 towards a reel 20where it is wound forming a roll that is ready for utilization indifferent applications.

Before reaching reel 20, the copper sheet passes through a hardeningdevice k and a device I for trimming its edges.

The hardening device k is formed by a cylinder 21 for supporting thesheet, upon which several frictioning arms 22 press, said arms beingangularly displaceable around a horizontal shaft 23 parallel to thecylinder, and yieldingly pressed thereagainst under the force of relatedtraction springs 24.

The shaft 23 on which said frictioning arms 22 are mounted, is in turnmounted on related guides arranged parallel to the sheet, in order toallow simultaneous angular displacement of said arms over the sheet,with an oscillating motion, said shaft being connected to driving means(not illustrated).

The trimming device 1 comprises a cylinder for sup porting the band andtwo circular rotating shears, one related to each marginal zone of thecopper sheet.

According to an alternative arrangement, the stirrer is composed by twosets of blades, one next to each lateral wall 11 of the cell c; each ofsaid blades 14 is formed by a lateral arm projecting from a verticalshaft 25 rotatively mounted on related supports 25a on the lateraladjacent wall 11 of the cell e. The top portion of said shaft whichprojects above the cell, has a short rod 26 articulated at its free endto a crank 27 that is common for all the blades located next to the samewall of the cell (FIGS. 3 and 6).

Both cranks 27 are related through adjacent ends to means that drivethem with oscillating motion.

No doubt that in the embodiments of this invention, some modificationscan be introduced in details of construction and shape of the apparatusfor producing endless electrolytic copper sheet, but never departingfrom the fundamental principles set forth in the following claims.

What is claimed is:

1. An apparatus for continuously producing a strip of electrolyticcopper, including an electrolytic tank, a travelling endless beltconveyor-like cathode having an upper and a lower substantiallyhorizontal strands and an external surface of the lower strand immersedin the electrolyte for continuously depositing thereon copper byelectrolysis as said surface is moved in immersed condition along saidtank and an inner surface opposite to said external surface, means tomove said belt conveyorlike cathode, anodes disposed in said tank inproximity of said immersed external surface, means for continuouslystripping the deposited copper in the form of band from said beltconveyor-like cathode, and wherein the improvement comprises said beltconveyor-like cathode in the form of horizontally extending endlessstainless steel belt having side-wall members of non-conducting elasticmaterial at each edge thereof, said side-wall members having each aportion extending in a direction substantially perpendicular to saidbelt cathode thereby to project from said inner surface and anotherportion extending substantially parallel to said belt cathode, saidanother portion having a slot adapted snugly to receive the edges ofsaid belt cathode, thereby preventing the electrolyte to reach saidinner surface and an edge portion of said external surface when saidexternal surface is immersed into the electrolyte, two horizontallyspaced drums at the end of said travelling belt conveyor-like cathodefor winding said belt cathode about said drums, a plurality of electriccontact members in contact with said inner surface, said electriccontact members extending over the entire operative width of said beltcathode and being arranged at regular intervals in the longitudinaldirection of the belt cathode and agitating means between said cathodebelt and said anodes.

2. An apparatus according to claim 1, wherein said electrolyte tank hason the bottom thereof a bed of lead and wherein said anodes are slabs ofcopper placed on said bed of lead.

(References on following page) References Cited UNITED STATES PATENTSEustis 204-13 Demel 20413 Yates 204-13 Hall 204-206 Venable 204206Sternfels 204-216 FOREIGN PATENTS 8/1953 France. 9/1953 France.

HOWARD S. WILLIAMS, Primary Examiner.

JOHN H. MACK, Examiner. Brietzke 15 -94 10 W. VAN SISE, AssistantExaminer.

